Etmax:- Yes I suspect you might be right it is more likley to be a surface effect than the sort of repair that replaces a substantial part of the tooth. When we get the facts voltage, current, pulse shape, contact method etc. then we will be better equipped to comment further. What I think will be fascinating for us NV memory watchers is what is being driven in and the mechanism responsible for that movement. the quote from King's College site reads "By accelerating the natural process by which calcium and phosphate minerals re-enter the tooth to repair a defect, the device boosts the tooth's natural repair process". Mixing the repair with the natural process will require an explanation.

Very interesting, my concerns wouldn't be things of reversed polarity, that's easily addressed, but more that teeth are very complex things with channels that allow fluid exchange between the nerve and exterior. What sort of streses are introduced when in stead of a thin layer of enamel is overlaid on dentine, a thick lump of enamel is used? Maybe it's only for small holes, or you go in for multi-stage treatment?

With respect to your request "How long will it take to build the tooth?" I have today submitted a list of questions to the dental group at King's College. I hope the answers will provide our readers with some quantitative rather than qualitative information about the process, including the answer to your timing question.

Very interesting research but, will it be commercially viable? There're a few options for fillings today amalgam (silver/mercury), resin and other composites . Most US dentists are moving away from amalgam for safety and cosmetic reasons. A resin/composite filling can be color matched. Basic fillings can be prepped and completed in about an hour.

How long will it take to build the tooth? Will the process allow for color matching? How will the cost compare to 'traditional' methods? In the US, the insurance drives people to chose the option that is covered. Insurance companies are slow to adopt new methods - most still consider composite fillings as 'extra'. I'm sure there are folks that will pay not to have "plastic" or "metal" in their mouth. Will that population be enough to help forge the commercial viability of this technology?

As this is work in progress, more details will follow and surely they must have involved eperienced dentist and surgeons in this invention. I got my teeth drilled yesrs back and it pains so much. Will this process be less painful as compared to the conventional one.

_hm:- Yes you make a good point, nerve damage has to be a consideration, I think it will depend on the mechanism. If it is electromigration then I would expect there would be current localization and high current density at the point on the surface of the tooth where the new material (mineral/clacium) is being driven in and much lower along the return path. If the mechanism is more plating like (electro-chemical) then the current density over a large area of the tooth surface would expected to be lower. Until we get the facts we have to consider the possibility,(continuing my NV memory analogy) that they have created a lateral structure wiith some sort of coaxial electrode where only current across the surface of the tooth is involved. Here is a speculative figure.